DESCRIPTION: The vascularization of engineered tissues is critical to the ultimate success of tissue engineering as an organ replacement therapy. The formation of new capillary vessels from existing vasculature, or angiogenesis, also is linked to the pathogenesis of numerous diseases including cancer, and is regulated by local cues within the tissue microenvironment. The general goal of this renewal project is to understand the mechanism by which local extracellular matrix (ECM) properties regulate endothelial cell invasion and sprout morphogenesis required in angiogenesis. The investigator has found that adhesion to ECM generates not only biochemical, but also mechanical signals that are important in driving endothelial cell function. Preliminary studies from the investigator suggest that ECM stiffness, adhesiveness, and degradability could be used to regulate the angiogenic invasion process through such materials by modulating contractile tension generated by the actin cytoskeleton. In this proposal, the investigator proposes to further investigate the role of these mechanical and adhesive cues in regulating angiogenic behaviors. The project proposes to investigate the contributions of different matrix properties and their cooperation in regulating angiogenesis using both in vitro and in vivo models, and to examine the role of cell generated forces in mediating the morphogenesis of developing vasculature. The investigator will examine whether these materials can be used to control the architecture of angiogenic vessels. Together, these studies will define the mechanisms by which local structural and mechanical properties within ECM modulate endothelial cell function and capillary morphogenesis, and establish new biomaterials design strategies to promote angiogenesis in ex-vivo engineered tissues as well as native ischemic tissues.